Instance Attribute Details

The temporary security credentials, which include an access key ID, a
secret access key, and a security (or session) token.

Note: The size of the security token that STS APIs return is not
fixed. We strongly recommend that you make no assumptions about the
maximum size. As of this writing, the typical size is less than 4096
bytes, but that can vary. Also, future updates to AWS might require
larger sizes.